Type I Chromosome 15q Deletion

About 70% of all PWS cases are the result of a de novo interstitial deletion involving the 15q11q13 region.[2] Most cases have similar/identical common deletion of about 4 Mbp with the same distal breakpoint and two alternative proximal breakpoints.[3] The deletion always involves the paternally derived chromosome 15. The same deletion is observed in patients with Angelman syndrome (AS) (see Angelman Syndrome), but in those cases the deleted chromosome is maternally derived.[7] The 15q deletion cases typically occur de novo and the recurrence risk for subsequent pregnancies is less than 1%.

Chromosomal rearrangements are seen in less than 1% of the PWS cases.

Type iia: Unbalanced translocation affecting chromosome 15.[8,12] In these cases, if the transmitting parent has a balanced translocation, the recurrence risk for PWS in the family can be as high as 50%.

Type lib: De novo balanced translocations affecting the paternally derived chromosome 15. Five such cases that resulted in PWS were reported.[3] in all cases of balanced translocations the translocation breakpoint lies within the locus of the gene SNURF-SNRPN. The balanced translocation cases do not have imprinting/ DNA methylation abnormalities (see Diagnostic Methods). The mechanism here appears to be the disruption of sequences in the SNURF-SNRPN locus and subsequent deficiency of one or more of the multiple transcripts that originate from this locus (see The PWS/AS Chromosomal Region).[3] For these de novo translocations the recurrence risk is less then 1%.

Getting Started With Dumbbells

Getting Started With Dumbbells

The use of dumbbells gives you a much more comprehensive strengthening effect because the workout engages your stabilizer muscles, in addition to the muscle you may be pin-pointing. Without all of the belts and artificial stabilizers of a machine, you also engage your core muscles, which are your body's natural stabilizers.

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